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Kilowatts (kW) measure power, kilowatt-hours (kWh) measure energy. Enter the power and the hours to get the energy, or choose the other direction to get the average power from an energy figure.

Enter your values

Pick what you know and what you want to find.
In kilowatts. Divide watts by 1000: 2500 W = 2.5 kW.
Where do I find this?

A device's label or manual shows its power in W or kW. 1 kW = 1000 W.

For a device that varies, use its average power over the hours.

How long the power was used. 24 hours is one day.
Where do I find this?

Use hours, not minutes: 90 minutes = 1.5 hours.

A day has 24 hours, a 30-day month 720, a year 8760.

Result

Enter your values to see the result.

Energy
– kWh
In watts
– W

Want this tracked for you? UtilityControl logs your meters and costs automatically.

How it is calculated

  • Energy (kWh) = power (kW) × time (h)
  • Average power (kW) = energy (kWh) ÷ time (h)
  • 1 kW = 1000 W

Example

A 2.5 kW device running 6 hours uses 2.5 × 6 = 15 kWh. The other way round, 15 kWh used over 6 hours is an average of 15 ÷ 6 = 2.5 kW.

What this estimate leaves out

kW is a rate and kWh is an amount, so they cannot be converted without a time. If the power changes during the period, the result is based on the average power you enter.

Written and reviewed by QLines, Cologne · Last reviewed

FAQ

Frequently Asked Questions

How do I convert kW to kWh?

Multiply the power in kilowatts by the hours it runs: kWh = kW × hours. A 2 kW heater running 3 hours uses 6 kWh.

What is the difference between kW and kWh?

A kilowatt (kW) is how fast energy is used, like speed. A kilowatt-hour (kWh) is the amount of energy used, like distance. Your electricity bill charges for kWh.

How many kWh is 1 kW for a day?

A constant 1 kW for 24 hours is 24 kWh. For a month of 30 days it is 720 kWh.

How do I convert kWh to kW?

Divide the energy in kWh by the time in hours. 15 kWh over 6 hours is an average of 2.5 kW.

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